It is not only that. There is a huge bias towards products written in C or C++. E.g. there are niche not-production-ready-yet products like ScyllaDB listed, but many popular, bigger and mature databases like HBase, ElasticSearch, Solr, H2, HSQLDB or Derby written in Java are missing.
Basically this is a table with cherry picked software projects where anything that isn't in ASM, C, C++, or Java is lumped into "Other". I don't know why anyone would create this useless page. It's in a style that honestly suggests "pre-internet" where all your knowledge came from curated sources. Nobody needs to curate this list.